Gas broiler

ABSTRACT

An oven unit in which a gas broiler is mounted above an oven cavity, inside a plenum and separated from the oven cavity by a radiation transparent panel, such as glass. The food in the oven is thus heated via radiation transmitted through the glass panel, and flue products from the broiler are kept above this panel and exit through flue outlets in the plenum area, without entering the oven cavity.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates generally to ovens for cooking food products, and more specifically, to an improved oven/broiler.

[0003] 2. Description of the Related Art

[0004] Gas ranges commonly have a gas broiler located within the upper portion of an oven cavity. Flue products from the broiler travel throughout the oven cavity, mixing with existing secondary air, heating food content, and exiting through flue outlets. A bake burner is usually located underneath the oven cavity, providing heat for baking and self-cleaning. Flue products from the bake burner travel into the oven cavity, mixing with existing secondary air, heating up food content, and exiting through flue outlets.

[0005] Unfortunately, this conventional design does not conveniently allow the gas bake burner and the gas broiler to operate simultaneously, because flue products from either heat source can prevent the other from proper ignition. For example, flue products from the bake burner can easily fill up the broiler cavity, making ignition difficult or impossible for the broiler.

[0006] Common ranges also often include a convection bake feature, by which a blower within the oven cavity can be turned on to circulate flue products and air inside the oven cavity. This “forced” convection is used to improve baking performance, by redistributing the heat evenly around the food content. However, a blower does not allow a gas convection broil feature, since the turbulence created by the blower can easily affect the gas broiler flame characteristics, resulting in blow-off, poor combustion, lifting, etc.

[0007] Finally, conventional design requires the flue products to have direct contact with food content, sometimes resulting in over-heating, or excess moisture. It presents a challenge to effectively direct and distribute the flue products to travel within the oven cavity. Since the flue products also come in direct contact with a thermostat sensing bulb, the broiler is more likely to cycle on and off. This on and off cycling can potentially negatively affect broiling performance, and also the lifetime of the broiler itself.

[0008] Thus there exists a need for an improved gas oven broiler which allows the broiler and oven to operate simultaneously and be more effective in heating food products.

SUMMARY OF THE INVENTION

[0009] The present invention comprises an oven unit in which a gas broiler, preferably infrared, is mounted above an oven cavity, inside a plenum and separated from the oven by a substantially radiation transparent panel such as glass. The food in the oven is thus heated via radiation generated by the broiler and transmitted through the glass panel, and flue products from the broiler are kept above this panel and exit through flue outlets in the plenum area, without entering the oven cavity.

[0010] The broiler may be designed to be gas-specific, or universal (with orifice change and air shutter adjustment). The infrared broiler includes a layer of porous combustion media made of heat absorbing mesh, ceramic tile, or other suitable materials. The media is heated by the combustion products to provide uniform radiant heating. After heating the media, the combustion products flow to one or more flue outlets. The broiler may be of atmospheric or powered burner type. To improve heating efficiency of the broiler, baffles and other reflective materials may be used to deflect radiation waves.

[0011] The broiler may be operated in conjunction with other heating sources, such as microwave, using suitable control mechanisms. It may cycle on and off, or function simultaneously with these other sources, since flue products from either source will not be able to travel to the other source, affecting the ignition process. These other heating sources may include oven convection bake burners, since air circulation inside the oven cavity will not affect flame characteristics in the broiler.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]FIG. 1 is a schematic, perspective view of the gas infrared broiler.

[0013]FIG. 2 is a schematic, perspective view of the entire oven with cutaway section to show the broiler.

[0014]FIG. 3 is a schematic, side view of the inside of the oven unit.

[0015]FIG. 4 is a schematic, front view of the inside of the oven unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0016] Referring to FIG. 1, there is illustrated an infrared broiler 12 having a combustion space 13 surrounded by a front wall 2, a back wall 6, two side-walls 4 and 8, a top wall 11, and a bottom wall formed by one or more layers of mesh 20. Extending through the front wall 2 and into the space 13 is a gas burner or venturi 18, having a generally elongated and cylindrically shaped body. A gas inlet or orifice 24 enters a forward end of the venturi, and an air shutter opening or inlet 26 is located immediately downstream of the gas orifice 24.

[0017] Preferably located inside the broiler 12 is an angled baffle 34, which spans horizontally between the front wall 2 and the back wall 6, and vertically between the top surface 11 and the mesh bottom surface 20. This baffle 34 has a plurality of holes, preferably four, to help uniform distribution of the air/gas mixture entering the combustion space 13. An optional metal plate 32 is also included in the preferred embodiment, located in about the center of the broiler just above or beneath the mesh 20.

[0018] Referring now to FIGS. 2 through 4, an oven unit 10 is illustrated, including the gas broiler 12 mounted in a plenum 29 above and separate from an oven cavity 40. The plenum includes sidewalls 29 a and a front wall 29 b, which separates the plenum from the venturi air inlet 26. As seen in FIG. 3, the broiler 12 is separated from the oven cavity by a radiation transparent panel 14, positioned over an opening 36 in the top panel 37 of the oven cavity 40. The mesh layer 20 of the broiler 12 is spaced from the glass panel 14 to define a gap 28 for flue products from the broiler open to the plenum 29 and leading to a pair of flue outlets 22 in the back of the oven unit 10. The flue outlets 22 may join oven cavity flue outlets 30, although this is not required. The oven unit includes an oven burner 41 illustrated in the present example in FIG. 3, below the bottom wall of the oven cavity.

[0019] During operation of the gas broiler 12, gas from the orifice 24 enters the venturi 18, drawing with it primary air through the air shutter opening 26 to mix with the stream of gas entering the broiler. This air-gas mixture then fills the broiler cavity and is ignited by the igniter 16.

[0020] The burning gases cause the mesh 20 to heat up rapidly to a red-hot glow, and send radiation downward through the glass panel 14 into the oven cavity 40 to heat food products in the oven, as illustrated by the arrows 43. Due to the panel 14 and the surrounding oven wall 37, the broiler flue products are prevented from entering the oven cavity 40, and instead flow through the mesh into the passage 28, through the plenum 29, and out through the flue outlets 22.

[0021] The optionally installed metal plate 32 in the center of the broiler adjacent the mesh 20 helps provide more uniform heat from the broiler into the oven. Also, note that the area of the panel 14 may be greater than that of the broiler lower wall. This enables radiant energy to better cover the oven cavity.

[0022] As another measure preferably taken to obtain uniform heating inside the broiler, the baffle 34 allows the gas-air mixture to pass through the holes in it and enter the other side, but limits the amount of gas-air mixture that passes through. This serves to keep the far side of the broiler from getting too hot due to a tendency of the gas-air mixture to collect on the far side of the broiler opposite from the venturi 18, without the baffle.

[0023] The panel 14 is preferably a highly transparent glass-ceramic having low thermal expansion and sufficient mechanical resistance for this application. As a result of its low thermal expansion, the material can be subjected to high temperature differences and still maintain excellent stability of form. One suitable material for the panel is sold under the trademark Robax. Of course, other materials may be employed which are substantially transparent to radiation and can withstand the temperatures involved, while maintaining adequate mechanical strength.

[0024] The mesh 20 used in the bottom of the broiler is preferably made of an alloy called Inconel which is generally used for applications that require a high resistance to heat and corrosion. Two preferable alloys of Inconel which can be used are alloy 600 and alloy 601, both of which have excellent mechanical properties, are easily formed, and can be used in applications involving temperatures above 2000° F. That material is also a good absorber and radiator of heat. The material should also be in a form that enables the flue products to readily flow therethrough. Of course, other materials, such as ceramic tile or other porous materials, having the necessary characteristics may be employed.

[0025] With the gas broiler substantially sealed from the oven gases, the broiler burner and the oven burner can be utilized simultaneously without ignition of either burner being affected by the other burner. This is so even with an oven employing a blower. Another advantage of the broiler is that its combustion gases do not contact the food in the oven. Contact can sometimes cause over-heating or adversely affect the food moisture. Also, since the flue products do not strike oven thermostat bulbs 44, the burner does not cycle on and off as does a conventional gas broiler. Such cycling can adversely affect broiling performance, and also the lifetime of the broiler itself.

[0026] While the invention disclosed herein has been described by means of specific embodiments and applications thereof, numerous modifications and variations could be made thereto by those skilled in the art without departing from the scope of the invention as set forth in the claims. For example, the broiler may be ignited by a hot surface ignitor, direct spark ignition, or other source of ignition. The system may be designed to operate with or without a catalyst to reduce undesirable flue products. The venturi may be centered or located asymmetrically in the broiler, and an adjustable or a nonadjustable air shutter may be used. 

What is claimed is:
 1. An oven unit comprising: a gas broiler for mounting above an oven cavity; and a panel for separating the broiler and the oven cavity to prevent broiler flue products from entering the oven cavity; said panel including a portion beneath the broiler which is substantially transparent to radiation so that radiation from the broiler heats items in the oven cavity.
 2. The unit of claim 1, including at least one flue outlet for ducting flue products away from the broiler.
 3. The unit of claim 1, wherein said broiler includes: side walls, a top wall, and a bottom wall forming a combustion space; and a venturi extending into said combustion space and having an outlet for introducing a combustible gas mixture into the space; said bottom wall including media configured to absorb heat from broiler combustion gases and to radiate the heat downwardly through said panel portion.
 4. The unit of claim 3, wherein said media is porous and spaced from said panel portion to enable flue products to flow out of the combustion space to a flue.
 5. The unit of claim 4 wherein said panel portion covers an area larger than that of said broiler bottom wall.
 6. The unit of claim 3, including an igniter for igniting the combustible gases entering the space.
 7. The unit of claim 1, wherein said broiler includes a layer of good heat conducting material which is heated by combustion gases in the broiler and radiates heat energy through said panel portion and into said oven cavity.
 8. The unit of claim 1, including walls defining an oven cavity, and a gas burner for heating the oven cavity.
 9. The unit of claim 1, wherein said broiler includes a bottom wall comprising a porous media which radiates heat downwardly through said panel while permitting combustion gases to exit the broiler.
 10. A method of making an oven unit, comprising: providing a gas burner above an oven cavity; and separating the gas burner from the oven cavity with a panel that blocks combustion gases from the gas burner from entering the oven cavity; and forming a portion of the panel with material which is substantially transparent to radiation that enables radiation from the gas burner to enter the oven cavity to heat items within the cavity.
 11. The method of claim 10, including positioning a layer of heat-conducting material between an outlet from the gas burner and the transparent panel portion; and providing a combustible gas igniter in a location to cause combustible products from the burner to ignite above the porous media to cause the media to absorb heat and radiate energy into the oven cavity.
 12. The method of claim 11, including providing a flue products outlet above said panel and in communication with a space between said media and said radiation transparent panel. 